1. Technical Field
This invention relates to refuse containers and the like, and more particularly to hinged assemblies for the lids of such containers.
2. Description of the Prior Art
Refuse collection is becoming increasingly mechanized. As little as ten years ago, laborers hoisted to their shoulders heavy steel cans filled with garbage and carried the containers to, and emptied the contents into, a truck parked at the curbside. This essentially manual system for transferring refuse from the customers' containers to the collection truck has rapidly become uneconomical in nations having rising wage rates and falling costs of automation.
Automated refuse collection systems are improving the efficiency of refuse collection and reducing the need for highly paid manual refuse collectors. In both semi-automated and fully automated refuse collection systems the entire customer base is provided with identical refuse containers, and the collection trucks are equipped with lifting mechanisms for automatically emptying such containers.
In a semi-automated refuse collection system, the filled refuse containers are manually positioned on the lifting mechanism on the truck. Known semi-automated containers are substantially rectangular, with a lifting receptacle located in the front vertical wall of the container. The lifting mechanism engages and locks into the lifting receptacle of a container, and lifts the container until it is inverted over and emptied into the receiving hopper of the truck. The container is then lowered and manually disengaged from the lifting mechanism, and manually returned to its original place.
Fully automated refuse collection systems eliminate the need for manual positioning of the containers adjacent the truck. A fully automated collection truck is equipped with a robotic-type manipulator disposed at the end of an articulated mechanical arm. Customers are required to place their containers at or near the curbside, where they can be reached by the manipulator. With the truck stopped near a container, the driver operates the arm and manipulator to securely grasp the container and lift and empty it into the truck, and then replaces the continer at the curbside. Fully automated collection systems require only one worker per truck, in contrast to the driver plus multiple laborers required by both manual and semi-automated systems.
Both semi-automated and fully automated refuse collection systems require that the containers used therein have hinged lids which can be readily opened when the container is emptied into the truck, and equally readily replaced to cover the empty container. In addition to a hinged lid, a semi-automated or fully automated refuse container is typically also provided with one or more wheels at the base of the container, and a horizontal handle along an upper edge of the container. By grasping the handle and tilting the container, customers can roll the container on its wheels to the curbside. For simplicity of manufacturing and assembly, it is advantageous to mount the hinged lid to pivot around the axis of the horizontal handle. Snyder et al U.S. Pat. No. 4,450,976 discloses a wheeled molded container with a hinged lid in which the hinge rod joining the container body and lid is partially exposed to function as a handle. The Snyder et al hinge rod extends through interconnected hinge portions of the container and the lid, pivotally coupling the container and lid. The hinge rod is exposed in regions between the interconnected hinge portions so that the rod can be grasped and function as a handle for manipulating the container. The Snyder et al container requires careful and accurate alignment during assembly. After molding, aligned apertures are bored through the hinge portions of the lid and container, and the hinge rod is then passed through the apertures and capped. Such alignment, boring and assembly necessarily increases the cost of producing the Snyder et al container.
Rotational molding techniques, when applied to thermoplastics such as high density, cross-linkable polyethylene or other polyolefins, allow production of plastic objects having substantially uniform wall thicknesses. Rotational molding involves rotating about at least two axes a heated mold containing a quantity of a thermoplastic. The multiaxial rotation spreads the melted plastic uniformly over the surface of the mold. Subsequent cooling of the mold solidifies the plastic against the mold, producing a solid plastic object. Rotationally molded plastic is both strong and durable. Further, rotationally molded plastic objects can include additional desirable features such as fire retardant additives, colors on request, or custom designs molded into the object. Rotational molding is a known method of producing strong, durable, attractive, and relatively lightweight refuse containers usable with semi-automated and fully automated refuse collection systems.